When an automobile engine misfires, it would be desirable to quickly and accurately identify the cylinder which is misfiring, so that repairs or correction of the problem could be quickly accomplished. In the past, various methods have been employed to accomplish this goal. The most common technique is to run the engine at a fairly low speed and successively disable the cylinders, one-by-one, and check for changes in motor sound and/or vibration, with disabling of the misfiring cylinder not causing any change, while the disabling of other cylinders producing further (intentional) misfiring and a change in engine sound or vibration. However, the foregoing method is time consuming; and, with intermittent misfiring conditions, it is difficult to identify the source of the problem.
Accordingly, a principal object of the present invention is to identify the particular cylinder causing misfiring conditions in engines.